Songbirds fly 3 times faster than expected

Published: Saturday, February 14, 2009, 16:42 [IST]

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Washington, Feb 14 (ANI): By tracking the migration of songbirds, scientists have found that they have, till now, underestimated the birds' flight performance dramatically, and have determined that the species actually fly 3 times faster than expected.

Bridget Stutchbury, a professor of biology in University of York's Faculty of Science and Engineering, and her team, fitted some songbirds with tiny geolocator backpacks, in order to track the migration route that the birds take.

"Never before has anyone been able to track songbirds for their entire migratory trip," said Stutchbury. "We're excited to achieve this scientific first," she added.

Stutchbury and her team mounted miniaturized geolocators on 14 wood thrushes and 20 purple martins, breeding in Pennsylvania during 2007, tracking the birds' fall takeoff, migration to South America, and journey back to North America.

The geolocators, which are smaller than a dime, detect light, allowing researchers to estimate birds' latitude and longitude by recording sunrise and sunset times.

The devices are mounted on birds' backs by looping thin straps around their legs. The weight of the geolocator rests at the base of the bird's spine, so as not to interfere with its balance.

In the summer of 2008, the team retrieved the geolocators from five wood thrushes and two purple martins and reconstructed individual migration routes and wintering locations.

Data from the geolocators indicated that songbirds can fly in excess of 500 km (311 miles) per day.revious studies estimated their flight performance at roughly 150 km (93 miles) per day.

The new study found that songbirds' overall migration rate was two to six times more rapid in spring than in fall.

"We were flabbergasted by the birds' spring return times. To have a bird leave Brazil on April 12 and be home by the end of the month was just astounding. We always assumed they left sometime in March," said Stutchbury.

She emphasized the importance of this research not only to protect at-risk species of songbirds, but also to gauge environmental concerns.

"Tracking birds to their wintering areas is also essential for predicting the impact of tropical habitat loss and climate change," she said.

"Until now, our hands have been tied in many ways, because we didn't know where the birds were going. They would just disappear and then come back in the spring. It's wonderful to now have a window into their journey," she added. (ANI)